Electronic counting system



y 1949- w. P. OVERBE-CK 0,7

ELECTRONIC COUNTING SYSTEM Filed June 11, 1943 2 Sheets-Sheet 1 Q): It

May 17, 1949- w. P. OVERBECK 7 I ELECTRONIC COUNTING SYSTEM Filed June11, 1945 2 Sheets-Sheet 2 Control rid Potevziziaz 41 1:1;Jzzmvxefsarriiidarziia? 1Z:T:' T: :.'::Z:

Patented May 17, 1949 UNITED STATES PATENT OFFICE ELECTRONIC COUNTINGSYSTEM Wilcox P. Overbeck, Chicago, 111., assignor to ResearchCorporation, New York, N. Y., a corporation of New York Application June11, 1948, Serial No. 490,505

Claims. (01. 235-92) 1 The present invention relates to electroniccounting systems, and more particularly to counting systems foroperation at extremely high speeds.

Electronic counting systems in general involve the use of electronictrigger circuits, each of which is capable of assuming either of twoconditions of stability. In the usual system, one condition of stabilityis satisfied when current flows to the anode and the second condition ofstability when no current flows to the anode, these two conditions beingrespectively designated as on" and oh? conditions. Although the triggercircuit forms the basis of the counting system, there are a number ofdifierent ways in which triggering action may be availed of to produce acounting action.

Counting systems, as heretofore constructed, may in general beclassified in either one of two types, namely, the ring or chain system,and the binary or scale-of-two system.

The ring or chain system has in each stage a number of trigger circuits(ten for the decimal system) in which only one tube is in conductingcondition. The circuits are so arranged that when an initiating pulse isapplied to all of them, it causes the next tube beyond the conductingtube to be itself converted to the conducting condition, the previouslyconducting tube being then extinguished. In some systems, the selectiveaction occurs by virtue of a priming arrangement,

the circuits being so arranged that only'a primed tube will be convertedby the action of the initiating pulse. In any case, the extinction ofthe previously conducting tube follows the conversion of the next tubeto the conducting condition, for which purpose a transfer pulse or itsequivalent is generated by the conversion of the new tube. In mostinstances the time required for extinction of the previously conductingtube must be greater than the length of the initiating pulse. Alimitation is, therefore, placed upon the rapidity of the initiatingpulses, and this places a limit on the counting speed of the system.

It will be understood that for counting numbers larger than the numberof tubes in the chain, additional stages will be used with appropriatecarry-over devices. Since the carry-over stages necessarily operate atlower speeds than the initial stage, the speed limitation is usuallysignificant for the initial stage only.

In the binary or scale-of-two system, the first stage comprises a singlecircuit, usually involving two tubes, one of which is in the conductingand the other in the non-conducting condition. An

initiating pulse immediately converts the conducting tube to thenon-conducting condition, and the non-conducting tube to the conductingcondition. The entire action occurs within the duration of theinitiating pulse. Hence, the

speed limitation is much less severe than in the case of the countingring. Additional stages may be used to count up to any desired number.The principal disadvantage of the binary system is in its awkwardcounting scale, and ultimate conversion to the decimal scale isnecessary for practical reasons.

The principal object of the present invention is to provide a countingsystem in which the speed of operation is not limited by the necessityfor successive triggering actions, and which, therefore, has the speedadvantages of the binary system, but which may be operated in othernumber scales.

With this object in view, the persent invention contemplates the use ofa counting system involving an odd number of tubes and with a peculiarprogression of triggering action, whereby the counting steps may beaccomplished in a time not substantially greater than the duration ofthe initiating pulse. Since, as will hereinafter appear, this systemrequires an odd number of tubes, the counting may be accomplished in thescale of 3, 5, 7, 9, or any other odd number, although the distinctivecharacteristics of the system are most apparent when the scale is 5 orgreater. In order to make use of the system for practical countingpurposes, it is preferable to use a quintary system (scale-of-five),which may be used in combination with a binary system to obtain resultsin the decimal number system.

In the accompanying drawings, Fig. 1 is a diagram of th preferred formof system, and Figs. 2, 3, 4, 5 and 6 are diagrams illustrating thesequence of operations.

The system shown in Fig. 1 comprises an input circuit III ofconventional form, leading to a binary counting circuit having the tubesB and B The output of the binary circuit is fed through a coupling tubeC to the quintary circuit involving five tubes designated Q to Q Eachtube is preferably a pentode, having a cathode I2, a control grid M, ascreen grid [6, a suppressor grid I8 and an anode 20. Although thecontrol grid and the suppressor grid are herein designated by the termsusually applied in the tube art, both grids are used asconduction-controlling electrodes, as will hereinafter appear.

For the present, only the quintary circuit will be described, since thisis capable of being operated by impulses from any input circuit. Theinput to the quintary system comprises a line 22 connected byindependent condensers 24 to the control grids of the several pentodes.The several control grids are connected through independent resistors 28to a source of negative bias potential Ec. The several screen grids areconnected by direct connections 30 to a source of positive potential Eb.The potential Eb is also applied to the anodes of the several tubesthrough a connection 3| and independent resistors 32. Each anode isconnected through a parallel condenser 34 and resistor 38 with thecontrol grid of the next succeeding tube and through a parallelcondenser 38 and resistor 40 with the suppressor grid of the nextpreceding tube. The suppressor grids are connected through resistors 4|with a line 43 connected with a source of negative biasing potential Es.It will be noted that the same connections are made between tubes Q andQ whereby a ring or closed chain of five tubes is formed.

As will presently appear, the circuit will look into any one of fivestable conditions in which the anode circuits of two non-adjacent tubesare conducting and the anode circuits of the other three tubes arenon-conducting. A tube is capable of anode conduction only when both itscontrol and suppressor grids are at positive potential.

In Fig. 1 certain grid potentials are indicated, these being such as toshow tubes Q and Q in conductin condition, and the remaining tubes innon-conducting condition. Tube Q has its control grid positive and itssuppressor grid negative, tube Q 'has both grids negative, and tube Qhas its control grid negative and suppressor grid positive. Theconducting tubes Q and Q have both control and suppressor gridspositive. The flow of current to the anode of tube Q through its anoderesistor 32 holds its anode potential low and therefore. maintainsnegative potentials on the suppressor grid of Q and the control grid ofQ Likewise, the suppressor grid of Q and the control grid of Q are heldnegative by anode conduction of tube Q Conversely, the control andsuppressor grids of Q and Q are positive, because of the high anodepotentials of tubes Q Q and Q which are nonconducting.

The particular condition shown in Fig. 1 is diagrammatically illustratedin Fig. 2, wherein a dark circle represents an "off or non-conductingtube and a light circle an on or conducting tube. Considering the tubesas existing in a ring or chain, it will be noted that between Q and Qthere is a single oif" tube Q but between Q and Q there are two ofi"tubes, Q and Q Thus Q and Q may be said to represent a double gapbetween two conducting tubes of the chain. This arrangement is entirelygeneral, regardless of how many tubes there are in the chain, 50 long asthe total number is odd. That is, the tubes will be alternately on andofif with the exception of two adjacent oil tubes at some point. Theposition of the two off tubes is determinative of the number of countedpulses.

With the tubes as shown in Fig. 2, assume that a positive pulse isapplied over the input line 22. Two possible modes of operation may nowbe followed, depending on the values of the voltages applied to theseveral electrodes of the tubes. The simplest mode of operation, whichwill now be described, results in a peculiar stepping sequence, wherebythe first tube of the double gap becomes conducting. Thus on the firstpulse, Q goes off and Q goes on, so that the double gap is now at Q andQ, as shown in Fig. 3. The next pulse turns Q oil and Q on (Fig. 4).This sequence continues until after five pulses, the original conditionof Fig. 2 is restored. This sequence occurs when the normal potentialson the control and suppressor grids are fairly high.

The foregoin operations are illustrated by the graphs of Fig. 5, showingin solid lines the control grid potentials and in dotted lines thesuppressor grid potentials for each of the five tubes. These potentialsare illustrated for the condition of Fig. 1 up to a time To. At To apositive initiating pulse is assumed to be applied to the tubes, leadingto the condition illustrated at the right hand side of each graph. Priorto To, in Q the suppressor grid is at its full negative bias potential,butits control grid is slightly positive because the anode potential ofQ is high. (It will be understood that because of grid conduction, thepositive potential on any grid never rises above a small value.) In Qboth grids are slightly positive, because the tube on each side has ahigh anode potential. For Q both grids are negativebecause the tube isincluded between two conducting tubes for which the anode potential islow. Q is the same as Q and for Q the control grid is negative but thesuppressor grid is slightly positive. A pulse applied at time To has noeffect on Q except momentarily to increase the potential on the controlgrid by a slight amount. The pulse, however, raises the potential on thecontrol grid of Q from a negative to a slightly positive value, therebycausing Q to become conducting, with the immediate consequence ofcausing the control grid of Q to become negative and the suppressor gridof Q to become negative. For Q the pulse causes the control grid tobecome momentarily positive, but since Q is conducting, this positivepotential for Q cannot be maintained. The suppressor grid of Q becomespositive by virtue of the extinction of Q. In an extremely short time Qassumes the condition previously held by Q Q assumes the conditionpreviously held by Q. Each tube assumes the condition formerly assumedby the second tube to the right, the shift being indicated by thefollowing diagram:

Number or pulses rei f eeived con no on In the second mode of operation,the negative bias potentials applied to the screen and suppressor gridsare somewhat lower than the potentials that are applied in the firstsystem described above. This results in a somewhat different sequence ofoperations, in that an incoming pulse results in both conducting tubesbeing turned oil and the tubes adjacent thereto being turned on. Thus,from the condition of Fig. 2, an incoming pulse will turn off tubes Q 5and Q and ignite tubes Q and Q, leaving Q unignited.

Fig. 6 is a grid potential diagram for this second mode of operation.The grid potentials prior to Tocorrespond to the condition shown in Fig.2. A pulse is received at To. A short time thereafter, at T1, theconditions are momentarily similar to those shown in the right-hand partof Fig.

5. In the tube Q however, the applied negative a potential Ec is notsufiicient to swin the control grid to the full negative potentialillustrated by Fig. 5. Since the tube is obliged to assume a conditionof stability, if the grid cannot go negative to the full extent, it mustswing back to the positive condition, as illustrated by the diagramafter the time T1. conducting and necessarily affects the operation ofthe two adjacent tubes Q and Q Ultimately, the system must reach acondition in which the potentials on the grids of the several tubes arecompatible with maintenance of stability. This condition is asillustrated in the right-hand part of Fig. 6.

In Fig. 6, the operation of the tube Q in swinging its control rid backto the positive potential produces a result exactly like the applicationof another pulse in Fig. 5. A single initiating pulse results inshifting from the condition of Fig. 2 to that of Fig. 4. A diagramillustrating the progression for a single-pulse is as follows:

meaning that tube Q momentarily assumes the condition formerly held by Qand then assumes the stable condition formerly held by Q-'.

It will be observed from Fig. 6 that the time required for operation inthe second method is slightly reater than that required for the firstmethod. Since the second method operates like two steps of the firstmethod, its counting speed is in general reduced by about one-half. Thisreduction in counting speed is, however, balanced by the fact that thesystem, when set for operation under the conditions of Fig. 6, issomewhat more reliable, in that it will operate in the designated mannerfor wider variations of electrode potentials. The system indicated byFig. 5, while somewhat more rapid, requires that the screen andsuppressor grid potentials be held within fairly close limits.

A schedule of operations for the second method, starting with thecondition of Fig. 2, is as follows:

Number of T ubes in gf za conduction The tube Q then becomes pulse issimply to advance the double gap by one step.

Although a quintary system has been shown, it will be understood that itmay be applied to any odd number of tubes. It is not applicable to aneven number of tubes, since such a system would not provide a doublegap; alternate tubes would be off and on, and the same results would beobtained as in a conventional binary system.

The use of five tubes (quintary operation) is preferred, because itpermits combination with a binary system to count in the scale of ten.The binary system represented by tubes B and B and their accompanyingconnections is entirely conventional. In one stable condition, 13 is onand B is off. The action of a pulse applied at the input In is to turn Boff and B on. When B goes on, as it will for every alternate pulse, ittransmits a negative pulse to the control grid of the coupling tube C,thus turning C off and transmitting a positive pulse to the inputcircuit 20 leadin to the control grids of the tubes of the quintarycircuit. The next pulse at Ill turns B on and B off. When B is turnedoff, a positive pulse is fed to the control grid of C but, since thatgrid is at cathode potential and C is already fully conducting, noappreciable efiect is observed at the anode of C and no pulse istransmitted to the quintary section. Thus, each incoming pulse appliedto the circuit l0 operates the binary system in the usual manner, andevery second pulse causes the transmission of an activating pulse to thequintary circuit. The number of pulses may be counted by observing theconducting tubes in both the binary and quintary circuits.

A feature of importance is that the pulses for operating the quintarycircuit result only from the binary circuit and the coupling tube and donot depend in any way on the initiating impulses applied to the inputcircuit l0. Therefore, the operations in the quintary circuit maycontinue beyond the duration of the pulses applied to the binarycircuit. This is important in considering the second mode of operationof the quintary circuit which, as heretofore stated, is somewhat slowerthan the first method. Since the quintary circuit is actuated only onevery alternate pulse, and sincethe initiating pulses do not get throughto the quintary circuit, this reduction in speed imposes no significantspeed limitation on the inherent high speed operation of the binarycircuit.

Suitable indicating means may be used to indicate the number of pulses.A simple form of indicating circuit is shown in Fig. 1. A connection 42is run from the lower end of each anode resistor 32 to the junctionpoint of two resistors 44, 46. There are two such resistors bridgedbetween each two adjacent anodes. All ten of the resistors are connectedin series in a closed ring. Indicator leads 48, 50, 52, 54 and 56 aretaken off at the left-hand ends of the resistors 4'4.

As previously described, there are two adjacent "ofl tubes in thequintary chain, for example, Q and Q in Fig. 1. .The potential of lead48 is therefore the full anode potential Eb. The other three tubes Q Qand Q are alternately on and off, so that their anodes are alternatelyat low and high potentials. Consequently, leads 50, 52, 54 and 5B are atthe average of the high and low potentials. In any case, the lead whichis at high potentialindicates the position of the double gap. Anysuitable means may be used to give a visible indication of the singlelead that is at the high potential, here illustrated as individualvoltmeters 58. If desired, neon lamps may be used which, because of thefact that they become conducting only under potentials reater than theignition potential, will indicate only the high potential lead.

The indicating circuits above described are applied only to the quintarysystem. For the complete binary-quintary system, high potential on thenth lead shows that 2n r 2n+1 pulses have been counted, the exact numberbeing determined by reference to the condition of the binary tubes. Asuitable carry-over device leading to a subsequent circuit may beoperated upon the raising of the fifth indicatin lead to the highpotential.

In summarizing the foregoing description, it

will be observed that the quintary section, which forms the principalfeature of the invention, is composed of five elemental triggercircuits, each of which is capable of assuming either of two conditionsof stability. The condition assumed by any of the elemental circuits,however, is not independent of the other circuits in the system, but isdictated by the potential relations existing in the system as a whole.Upon the application of an initiating pulse the potential relations areupset simultaneously in the entire system. Thus the entire quintarysection may be viewed as a single trigger circuit having five conditionsof stability (or more generally, as many conditions of stability asthere are elemental tube circuits). It is this fact which makes forexceptionally highspeed operation, since all elements of the system areconverted immediately to the new conditions upon reception of a pulse,without the necessity of depending on a progressive action through theseveral tubes.

It will be understood that the particular embodiment herein shown isillustrative only and may be varied within the purview of the invention,as defined in the appended claims.

Having thus described my invention, I claim:

1. A counting system comprising an odd number, five or more, of triggercircuits each capable of assuming a conducting and a non-conductingcondition of stability, conduction-controlling means for each circuit,connections between each circuit and the conduction-controlling means ofadjacent circuits to establish difierent conditions of stability foralternate trigger circuits except for two adjacent circuits which are inthe same condition of stability, and means responsive to an initiatingpulse to affect the position of said adjacent circuits in relation tothe other trigger circuits in the system.

2. A counting system comprising an odd number, five or more, ofelectronic trigger circuits, each capable of assuming a conducting and anon-conducting condition of stability, conduction-controlling means foreach cricuit, connections between each circuit and theconductioncontrolling means of adjacent circuits to establish alternateconducting and non-conducting conditions in the several circuits exceptfor two adjacent circuits which are in the non-conducting condition, andmeans responsive to an initiating pulse to shift the relation ofadjacent nonconducting trigger circuits in the system.

3. A counting system comprising an odd number, five or more, ofelectronic trigger circuits, each having an anode and capable of stableoperation at high or low anode potential, conductioncontrolling meansfor each trigger circuit, connections between theanode of each circuitand the conduction-controlling means of adjacent circuits to establishthe high-anode-potential condition in any circuit adjacent to a circuitin which the condition of low anode potential exists,

whereby two adjacent anodes in the system are at high potential, meansfor applying an input pulse to the several trigger circuits, and meansresponsive to said pulse to shift the condition of adjacent high anodepotentials to other anodes in the system.

4. A counting system comprising an odd number, five or more, ofelectronic trigger circuits, each having a tube with an anode andconduction-controlling means, each circuit being capable of assumingeither a stable conducting condition or a stable non-conductingcondition, connections between the anode of each tube and theconduction-controlling means of adjacent tubes to establish theconducting condition only in each of those trigger circuits which areincludedbetween two circuits in the non-conducting condition, wherebythe system at any time has two adjacent tubes in the non-conductingcondition and the remaining tubes alternately in conducting andnon-conducting condition, means for applying an input pulse to theseveral trigger circuits, and means responsive to said pulse forshifting the condition of adjacent non-conduction to other tubes in thesystem.

5. A counting system comprising an odd number, five or more, ofelectronic trigger circuits, each having an anode, a control grid and asuppressor grid, each circuit being capable of stable operation at highor low anode potential, connections from the anode of each circuit tothe control grid of one adjacent circuit and to the suppressor grid ofthe other adjacent circuit, said connections establishing the conditionof high anode potential in two circuits adjacent to circuits at lowanode potential, the remaining circuits being alternately at high andlow anode potential, means for applying an input pulse to the severalcircuits, and means responsive to said pulse for shifting the relationof stability conditions in the circuits in the system.

6. A counting system comprising an odd number, five or more, ofelectronic trigger circuits, each having an anode, a control grid and a.suppressor grid, each circuit being capable of stable operation at highor low anode potential, connections from the anode of each circuit tothe control grid of one adjacent circuit and to the suppressor grid ofthe other adjacent circuit, an anode being capable of assuming thelow-potential condition only when its control grid and suppressor gridare both at positive potentials, whereby the circuits are alternately athigh and low anode potential except for two adjacent circuits which areat high anode potential, means for applying an input pulse to theseveral circuits, and means responsive to said pulse for shifting thestability conditions in the circuits of the system.

7. An electronic counting system comprising an odd number, five or more,of elemental circuits, each including an anode and twoconduction-controlling electrodes, each circuit being capable ofassuming two conditions of stability,

namely, a condition in which the anode is conducitng when both of itsconduction-controlling electrodes are positive, and a condition in whichthe anode is non-conducting when either of its conduction-controllingelectrodes is negative, connections from each anode to oneconductioncontrolling electrode of one adjacent circuit and to the otherconduction-controlling electrode of the other adjacent circuit, a sourceof positive potential for the anodes, sources of negative potential forthe conduction-controlling electrodes, whereby the anodes arealternately conducting and non-conducting, except for two adjacentanodes which are non-conducting, and resistor means between saidpotential sources and the corresponding electrodes, an input circuitconnected with corresponding conduction-controlling electrodes of theseveral circuits.

8. An electronic counting system comprising an odd number of elementalcircuits in a closed chain, each including an anode and twoconduction-controlling electrodes, each circuit being capable ofassuming two conditions of stability, namely, a condition in which theanode is conducting and at low potential when both of itsconduction-controlling electrodes are positive, and a condition in whichthe anode is non-conducting and at high potential when either of itsconduction-controlling electrodes is negative, connections from eachanode to one conductioncontrolling electrode of one adjacent circuit andto the other conduction-controlling electrode of the other adjacentcircuit to establish the highanode-potential condition in any circuitadjacent to a circuit in which the condition of low-anodepotentialexists, whereby two adjacent anodes in the system are at high potential,a source of positive potential for the anodes, sources of negativepotential for the conduction-controlling electrodes. resistor meansbetween said potential sources and the corresponding electrodes, aninput circuit connected with corresponding conduction-controllingelectrodes of the several circuits, a bridge connection between each twoadjacent anodes, and indicator means connected at an intermediate pointof each bridge circuit to indicate the position of the two adjacentanodes which are in the high-potential condition.

9. An electronic counting system comprising an odd number of electronictubes (n+1, where n is an even number greater than two), each of saidtubes having an anode, a cathode, and two control electrodes,connections from each of said anodes to control electrodes of two othertubes of the group, said connections providing the system with n+1stable conditions, in each of which tubes are conducting and tubes arenon-conducting, and input means for applying pulses to said controlelectrodes to cause the system to shift from one of said stableconditions to anoher.

10. A counting system comprising an odd number, five or more, ofelectronic trigger circuits, each having an anode and capable of stableoperation at high or low anode potential, conduction-controlling meansfor each trigger circuit, connections between the anode of each circuitand the conduction-controlling means of adjacent circuits to establishthe low-anode-potential condition only in each of those circuits whichare included between two circuits in high-anode-potential condition,whereby two adjacent anodes in the system are at high potential, meansfor applying an input pulse to the several trigger circuits, and meansresponsive to said pulse to shift the condition of adjacent high anodepotentials to other anodes in the system.

WILCOX P. OVERBECK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,932,589 Holden Oct. 31, 19332,053,156 Livingston Sept. 1, 1936 2,293,177 Skellett Aug. 18, 19422,306,386 Hollywood Dec. 29, 1942 2,310,105 Michel Feb. 2, 19432,329,792 Skellett Sept. 21, 1943 FOREIGN PATENTS Number Country Date214,631 Germany Oct. 14, 1909

